Process for the manufacture of waterinsoluble azo-dyestuffs



'idine, piperazine or pyridine.

United States Patent ()filice 3,120,508 Patented Feb. 4, 1964 3,12%,508PROtJESS FOR TEE MANUFACTURE F WATER- llNSULUliLE AZO-DYESTUFFS @sltarBraun, Rudolf Frank, and Fritz fisterloh, all of Frankfurt am Main,Germany, assignors to Farbwerke Hoechst Aktiengesellschaft vormalsMeister Lucius & Bruning, Frankfurt am Main, Germany, a corporation ofGermany No Drawing. Filed Aug. 16., 1960, Ser. No. 49,827 (llaimspriority, application Germany Aug. 20, 1959 Claims. (Cl, 260-161) FromGerman Patents 889,042 and 930,998 it is known to use surface-activesubstances as emulsifiers together with oils in the manufacture ofwater-insoluble aZo-dyestuffs having a soft grain.

Now, we have found that water-insoluble azo-dyestuifs having aparticularly high tinctorial strength can be prepared by adding duringthe coupling cationic surfaceactive compounds without simultaneouslyusing oils. It was not to be expected that by the mere addition ofrelatively small quantities of cation-active compounds such an increasein the tinctorial strength of up to 40% would be achieved. The cationicsurface-active compounds are generally added in quantities of about 1 toabout preferably 1 to about 3%, referred to the dry dyestuff.

As cationic surface-active compounds there enter into considerationpractically all such substances known, for example, all the substancesof this kind described in the book Surface-Active Agents and Detergentsby A. M. Schwartz, J. W. Perry and l. Berch, vol. II (1958), pages 103to 119.

Suitable cationic surface-active substances are, for example, aminocompounds that contain long-chained aliphatic rests of about 10 to 18carbon atoms, or also the salts of such nitrogen compounds withcarboxylic acids, such, for example, as formic acid, acetic acid, oleicacid, tallow fatty acid, lactic acid or mineral acids, for example,hydrochloric acid. In the first instance there enter into consideration:fatty amines, for example, coconut oil amine, oleyl amine, stearylamine, and tallow fat amine, as well as the secondary and tertiaryamines or quaternary ammonium compounds derived therefrom that may carryas substituents aliphatic, aromatic or oxethylated radicals, forexample, alkyldimethyloxethylammonium chloride. Suitable are alsooxethylated fatty amines in their secondary, tertiary or quaternaryform. There are further mentioned by way of example: the condensationproducts of long-chained, in case also unsaturated, carboxylic acidswith amines, in particular alkylenediarnines, alkylenetriamines, oralkylenepolyamines containing alkylene radicals of low molecular weight,for example, ethylene diamine, diethylene triamine, etc., as well as thesecondary, tertiary or quaternary amines formed by alkylation of thementioned condensation products, especially in the form of theirWater-soluble salts with the above-mentioned acids. Further, there maybe used fatty acid amides and esters of long-chained carboxylic acidsWith alkylol amines, for example, triethanolaminoleate, -stearate, andthe like, further also cyclical, nitrogencontaining compounds, forexample, long-chained rests containing derivatives of morpholine,imidazoline, piper- The above-mentioned amino compounds are usedpreferably in the. form of their carboxylic or hydrochloric salts.

The mentioned surface-active salts of amines may be added to the diazocomponent or they may be added together with the acidic diazo solutionto the coupling component. It is, however, also possible to add thesurfaceactive salts of amines to the suspended coupling component or tothe alkaline solution thereof, to the precipitating acid, or even in thecourse of the coupling.

The process of the present invention can be applied without anyrestriction to all known insoluble azo-dyestuffs. By insolubleazo-dyestufi are meant such dyestuffs as are obtained by the coupling ofdiazo or tetra-azo compounds of amines that do not contain groupsimparting Water-solubility with the coupling components usually employedin the pigment chemistry. As coupling components, there may be used, forexample: naphthols, hydroxynaphthoic acid arylides, pyrazolones,acetoacetic acid arylides, and the like.

By the addition of surface-active salts of amines according to theinvention, the dyestuff being formed is influenced with regard to itsparticle size in surprisingly favorable manner so that substantial gainsin tinctorial strength are achieved and in many cases also purer shadesare obtained. By the reduction of the particle size the dry content ofthe press cakes is increased up to 40%. This saves pressing space andreduces the drying cost. The reduced particle size becomes apparent in aremarkable increase of the density of the dyestufi' powder which, due tothe reduction of the space required, brings obvious advantages inpacking, transportation and storage.

A dyestuff press cake prepared according to this invention isadvantageously distinguished from the usual press cakes by substantiallybetter temperature stability during the drying, which also entails agreater storability of the dyestuff powder. Furthermore, a dyestulfpowder prepared according to the invention is distinctly lesselectrostatically charged than an ordinary azo-dyestuff, which againentails a favorable result in that the dyestuff has a reduced tendencyto dusting during manufacture.

The fact is also very surprising that a clear acceleration of thereaction during the coupling is caused by the addition of thesurface-active salts of amines. The products prepared according to thepresent invention exhibit also the advantage, which is of importance forthe technical use, that the surface-active compounds added protect thedyestuff grains during grinding and triturating. Thus, for example, in aconventional trituration with a barytes lake the tinctorial strengthremains the same, Whereas it is reduced with the usual pigments. Withthe dyestuif preparations of the present invention, the well-knowndeadrubbing of the pigment does not occur. The dyestuff powders are lesssensible to higher temperatures since they maintain their originaltinctorial strength even after a four weeks heating to 60 0, whereaspowders prepared in ordinary manner then distinctly lose theirtinctorial strength.

The increase of the tinctorial strength achieved by the new processfurther entails the advantage that such pigments, compared with ordinaryaZo-dyestuffs, can be blended in higher ratios. Thus, for example, therecan be prepared 40% blends with substrata that have alfinity to varnish,for example, metal salts of organic soaps, resins and fatty acids, aswell as fatty oils or mineral oils in emulsified form, which havetinctorial strengths corresponding to that of an unblended pigmentprepared by the conventional coupling methods. For the blend there aresuitably used in general water-soluble salts, for example, sodium,potassium or ammonium salts, which are then transformed into thecorresponding difficultly-soluble heavy metal salts, for example,calcium, barium, nickel, strontium, magnesium, iron, chromium oraluminum salts. There may, of course, also be directly used thediificultly soluble salts formed previously. The blending may beeffected either in the coupling solution or even later in the presscake.

The following examples illustrate the invention but they are notintended to limit it thereto Example 1 A water-insoluble aZo-dyestuff isprepared by diazotiz ing 91.2 parts by weight of1-amino-2-nitro-4-methy1-benzene and coupling with 108 parts by weightof acetoacetylaminobenzene, by well stirring the coupling component intoa weakly acetic medium before introduction of the diazo-solution andthen adding 5 parts by weight of oleylaminacetate dissolved in hotwater. The coupling is effected at 20 C. and at a pH between 4.5 and5.5. After having terminated the addition of diazo-solution, the wholeis stirred for minutes, then filtered and washed neutral. A press cakeis obtained which has a dry content of 24.3%, whereas a press cakeprepared under equal conditions but without the addition ofoleylaminoacetate, has a dry content of 18.6% only. The press cake isdried at 60 C. There are obtained 204 parts by weight of a yellowpigment dyestutf which, when tirturated with oil, dyes a standard whitepigment about 40% stronger and with a distinctly purer shade than adyestutf coupled in the same maner but without oleylaminoacetate.

The dyestuff powder obtained after the grinding process distinguishesadvantageously from a powder prepared without the addition of cationiccompounds by an essentially higher density. Thus, for example, aquantity of about 72 kg. of dyestuff powder can be placed in a drum of400 liters capacity compared to about only 54 kg. of a dyestulf powderprepared in conventional manner.

This advantageous change of the structural state of the dyestuff pastesand powders obtained by the process of the present invention becomesalso apparent in a comparison of the specific surfaces and the meanparticle size of a dyestuif powder according to the present inventionwith those of conventional powders. Whereas the latter exhibits aspecific surface of about 17.3 m. g. and a mean particle size of about0.23311. the dyestuif powder prepared by the above described processexhibits a specific surface of 27.4 m. /g. and a mean particle size ofthe primary and secondary particles of 0.147

Instead of oleylaminacetate there may be used in the above workingmethod with the same result other fatty amino salts, for example,coconut oil amine, tallow fat amine and stearylamino-acetate, or thecorresponding formic or lactic salts. Furthermore, theacetoacetylaminobenzene may also first be dissolved in an alkalihydroxide solution, and then precipitated with acid, for example, formicacid, in which the cation-active additives are dissolved. Thecation-active additives may also be added to the alkaline solution ofthe coupling component either before precipitation with an acid ordissolved in the diazo solution, or simultaneously with thediazo-solution or in a later stage of the coupling process in dissolvedform.

During the coupling the dyestuif can be blended in the following manner:The coupling liquor is added with 106 cc. of a calcium chloride solutionof strength (prepared from commercial, anhydrous calcium chloride). Tothis liquor is then added within 30 minutes a solution of 239 parts byweight of sodium colophonate of 50% in 1.5 litres of water, the whole isstirred for 30 minutes, then filtered and washed neutral. After dryingand grinding, ther is obtained a dyestufif containing 59.0 parts byweight of pure dyestuff, 40 parts by weight of calciumcolophonate and 1part by weight of oleylaminacetate. Despite the large quantity ofextenders, the tinctorial strength of this dyestuif powder correspondsto that of an unblended dyestuif prepared according to conventionalprocesses.

The blending may, of course, also be effected by directly adding to thecoupling solution the previously prepared calcium-colophonate. The presscakes may as well also be blended by kneading with resin soap.

Instead of the calcium colophonate, there may also be used for theblending the corresponding barium, magnesium, strontium, zinc, cadmium,nickel, aluminum, iron or chromium salts of resinous acids or also thediflicultly soluble free resinous acids. Furthermore, there may also beused fatty acids or the diflicultly soluble salts thereof, for example,stearic, palmitic, coconut-oil fatty acid as well as fatty oils ormineral oils, suitably in emulsified form.

Example 2 A water-insoluble azo-dyestuff is prepared by diazotizing inconventional manner 86.5 parts by weight of 1-amino-2-nitro-4-chloro-benzene and coupling with 109 parts by weight of1-acetoacetylamino-2-chlorobenzene. The coupling component is dissolvedin water that has been added with one part by weight of the disodiumsalt of the ethylene diamine-tetraacetic acid. Shortly before adding thediazo solution, 2.5 parts by weight of tallow fat aminacetate in form ofan aqueous solution of 5% strength are added. The coupling proceeds at10-15 C. and in a pH range of 3.8 to 5.5. After having terminated theaddition of the diazo-solution, the whole is stirred for 15 minutes,filtered, washed and dried at 60 C. The yield is 196 parts by weight.

With a small addition of about 1.25% referred to the dry dyestui'f,there is already obtained a yellow pigment that exhibits in normal whiteblends a tinctorial strength stronger by about 25% and a purer shadethan a pigment prepared without addition of tallow fat aminacetate.

Example 3 A water-insoluble orange pigment is prepared by tetraazotizing76 parts by weight of 3,3-dichloro-4,4-diamidodiphenyl. The tetra-azosolution is added at 25 C. to an alkaline coupling solution consistingof 110 parts by weight of 1-phenyl-3-methyl-5-pyrazolone, 75 parts byweight of chalk and 12.0 parts by weight of oleylaminacetate, which isadded in the form of an aqueous solution of 10% strength. After theintroduction of the tetra-azo solution is terminated, the couplingliquor is adjusted by means of hydrochloric acid to a weakly acid valueof pH 1-2. The coupling solution is then heated to the boil, boiled forone hour, filtered, washed, and the press cake is dried at 60 C.

The above working method yields a soft pigment which, after having beenincorporated on the roller with rubber together with the requiredadditives and after vulcanization of the mixture gives a substantiallystronger shade than a pigment prepared without the cation-activecoupling additive. Instead of the oleylaminacetate there may also beused equal or smaller quantities of the following compounds: coconut oilaminacetate, tallow fat aminacetate or stearyl-aminacetate. Instead ofthe acetic salts there may also be used with the same result thelactates thereof.

Example 4 A coupling solution consisting of 1800 parts by weight ofwater, 131 parts by weight of sodium hydroxide solution (45 volumepercent) and 118 par-ts by Weight of acetoacetylamino-Z-methylbenzene isintroduced into a mixture of 200 parts by weight of water, 1200 parts byweight of ice, 67 parts by weight of glacial acetic acid and 5 parts byweight of sodium alkylsulfamidoacetate. To this mixture is added amixture of 56 parts by weight of glacial acetic acid and 106 parts byweight of sodium hydroxide solution (45 volume percent). Beforeintroducing the tetra-azo solution, which was prepared bytetraazotization of 76 parts by weight of 3,3-dichloro-4,4'-diaminodipheny1 in usual manner, the coupling solution isadded with 9.6 parts by weight of coconut fat aminoacetate in the formof an aqueous solution of 10% strength. After the coupling is complete,the mixture is boiled for one hour, filtered, well washed and thedyestufi press cake is dried at 60 C.

There is produced by the above working method a water-insolubleazo-pigment which, after incorporation with rubber with the additivesrequired on the threeroller mill yields yellow dyeings of a distinctlystronger and more vivid shade than those obtained with a pigmentprepared without addition of cation-active substances.

In the process described above, the coconut oil aminacetate may alsoadvantageously be dissolved in the glacial acetic acid used or it mayalso be added separately to the coupling solution at the same time asthe tetraazo-solution.

Example A water-insoluble =azo-dyeshufi is prepared by tetraazotizationof 76 parts by weight of 3,3'-dich1-oro-4,4-diaminodiphenyl. Thetetra-azo solution so obtained is added in the course of 1 /2 hours tothe coupling component which was prepared by dissolving 112.5 parts byweight of acetoacetyl-ammobenzene in 1500 parts by weight of water and76 parts by weight of sodium hy droxide solution (37.5 B.). To thisalkaline solution of the coupling component are added, after dilution,further 1500 parts by weight of water and, after cooling with ice to 5to 6 C., 10 parts by weight of coconut oil aminacetate dissolved inwater and the acetoacetylaminobenzene is precipitated by adding parts byWeight of glacial acetic acid. After addition of 1 mole of sodiumacetate, the solution is added at 12 C. with the tetra-azo solution. Thewhole is stirred for 30 minutes, filtered, washed neutral and dried atC.

There are obtained parts by weight of a yellow azo-dyestuif, which dyesa standard white pigment distinctly stronger shades than a similardyestuff prepared without addition of coconut oil aminacetate.

When increasing the quantity of coconut oil aminacetate to, for example,15 parts by weight, there is achieved a further gain in tinctorialstrength.

Instead of the coconut oil aminacetate, there may be used with the sameresult, for example, oleyiaminacetate, tallow fat aminacetate andstearylaminacetate, or even the lactic salts thereof. I

Instead of being added to the alkaline coupling solution, theabove-mentioned cationic additives may either be added to theprecipitating vinegar or also after precipitation of the couplingcomponent or they may be used together with the tetra-azo solution.

We claim:

1. In a process for preparing water-insoluble azo-dyestufis, theimprovement of adding, to a coupling mixture, a surface active salt of aprimary aliphatic amine of from 10 to 18 carbon atoms with a carboxylicacid of the group consisting of formic acid, acetic acid, and lacticacid in an amount of from 1 to 10% by weight referred to the finalazo-dyestuff.

2. The process as defined in claim 1, wherein the surface active salt isoleylamino acetate.

3. The process as defined in claim 1, wherein the surface active salt isadded to the diazo component before coupling.

4. The process as defined in claim 1, wherein the sur face active saltis added to the coupling component before coupling.

5. The process as defined in claim 1, wherein the surface active salt isadded to the coupling mixture in the course of the coupling.

Schwartz et al.: Surface-Active Agents and Detergents, vol. II (1958),pp. 103 to 119, TP 149 S3 C7.

1. IN A PROCESS FOR PREPARING WATER-INSOLUBLE AZO-DYESTUFFS, THEIMPROVEMENT OF ADDING, TO A COUPLING MIXTURE, A SURFACE ACTIVE SALT OF APRIMARY ALIPHATIC AMINE OF FROM 10 TO 18 CARBON ATOMS WITH A CARBOXYLICACID OF THE GROUP CONSISTING OF FORMIC ACID, ACETIC ACID, AND LACTICACID IN AN AMOUNT OF FROM 1 TO 10% BY WEIGHT REFERRED TO THE FINALAZO-DYESTUFF.